Dr. H. Fol on the Family 'Tintinnodea. 85 
and described by Hiickel, notwithstanding the few differences 
that will be remarked in the form and proportions of the test, 
because I have now arrived at a certainty that Hickel’s 
drawings were made rather carelessly, and must not be taken 
“au pied de la lettre.” 
The two nuclei are placed in the hinder part of the body 
and attached to the two opposite walls. One of them is gene- 
rally placed a little behind the other. 
I profit by this opportunity to rectify my previous state- 
ments as to the dimensions of the test of this species. The 
length of this test reaches 0°16, and its width at the orifice 
0-1 millim. 
Codonella ventricosa. (Pl. IV. fig. 12.) 
(Tintinnus ventricosus, Clap. & Lachm.) 
The test is much thicker than that of C. campanula, and 
strongly incrusted with small granules of very unequal size. 
The constricted edge is smooth; and it is upon this non- 
incrusted part that the flexible membrane is implanted. The 
smooth zone resembles a cravat, and the membrane a straight 
collar rising above it. ‘The figure represents this membrane 
slightly folded. When the animal expands, the membrane 
becomes elevated in a cylindrical form; when the animal 
withdraws to the bottom of its test, the membrane folds in- 
wards and completely closes the entrance to the test. This 
membrane is incrusted with little brilliant elongated bodies, 
all directed perpendicularly to the edge of the membrane. 
The test is 0°075 millim. in length to the base of the mem- 
brane, which is 0-015 millim. wide. The greatest width of 
the test is 0°07 millim. 
The animal presents two nuclei placed at the same level 
towards the middle of the body against the walls. 
I found this species in very great abundance at Villafranca. 
Codonella nucula, sp.n. (Pl. IV. fig. 13.) 
This species much resembles the preceding, except as 
regards its dimensions. ‘The incrusting bodies are a little 
more scattered, and the flexible membrane is relatively wider. 
The length of the test alone is 0-04 miilim., that of the mem- 
brane 0:015 millim., and the greatest width of the test 0°033 
millim. 
One might be tempted to take this form for a young state 
of the preceding species, if it were not that, notwithstanding 
the great abundance in which these two species occur, inter- 
mediate forms are entirely wanting. Moreover I have never, 
